The Coriolis sass flowaeter is modelled using the theory of vibrating beams. Tube deformations for the fundamental mode and the next two nodes of natural (out-of-plane) vibration are worked out for many tube geometries. An improved model taking into account the effects of elastic boundary conditions and added masses of the electromagnetic drive and detectors is also discussed. A method for predicting the optimum detection positions is suggested in relation to signal-to-noise ratio. In addition, an argument for prediction of the effects of a dilute suspension of small bubbles or particles in the fluid is presented. Finally, experimental studies are conducted in order to demonstrate the validity of the theoretical models.

The motion of the free liquid surface inside a reservoir is called sloshing. Itis of large interest in different industrial fields such as satellite and spacecrafttrajectory control, automotive industry, nuclear engineering, buildingdesign, etc. The framework of propellant management on spacecraft is ofmain interest for this PhD thesis, even if its outcome can be applied to manyother fields concerned by sloshing.Being able to understand the behavior of the fluid in a reservoir subjectedto extreme environmental conditions means being able to predict its positionand topology inside the tank, for a given external and gravitationalacceleration and a determined thermodynamic condition. The predictionand control of this motion is far from being understood due to the differentparameters that play a role in the dynamic system such as the geometryof the container, the type of external excitation (shape, frequency contentand amplitude), the level of the liquid and finally the kind of liquid. In particular,the design of propulsion systems are affected by this phenomenon,still hampered by the unavailability of validated CFD models. Moreover theexisting experimental studies are mainly based on intrusive and local singlepoint measurement techniques, which give no information on the behaviorof the 3D liquid interface and on the velocity field inside the liquid phase.The main goal of this project has been to extend the experimental approachof liquid sloshing investigation in space propulsion, studying, developing andimproving non-intrusive measurement techniques for free surface behaviorand velocity characterization in the liquid phase. In particular, the free surfacebehavior have been studied by means of Laser Detection and Recordingtechnique (LeDaR), retrieving the profile of the interface over a line, andReference Image Topography technique (RIT), capturing the instantaneous3D interface shape. In addition, Particle Image Velocimetry (PIV) have beenused to measure the 2D velocity field in the main section of the reservoir.Tests performed with water were used as simpler test case to perform thetechniques while liquid nitrogen has been used as replacement uid havingphysical properties similar to real space propellants.The experimental problems of the selected measurement techniques relatedto the particular application have been addressed and a solution has beenproposed. Especially, the selection of tracers which could comply with theuse of a cryogenic fluid while for RIT the possibility to deal with circulardomains and to measure the absolute value of the liquid level. Finally, PIV in wavy ows needed to deal with dynamic curved interfaces for whicha widely-accepted processing algorithm was not available in literature andbesides, the choice of the particles and their seeding procedure in cryogenicsfluids had to be solved.Some applications are shown, which present the potentiality of the techniquesfor a new insight on sloshing flows with the future purpose of providingan accurate database for the verification and validation of numericalsimulations and a better understanding of the phenomena. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

This work presents the method of calculating the core loss in ferrite cores by using a linear and sinusoidal finite element solver based on the material property data (the complex permeability, the dielectric constant, and the AC conductivity) measured in the laboratory. Due to the lack of published material data and fundamental test procedures, this work also demonstrates the measurement techniques of material data which are necessary for the finite element analysis (FEA) of the ferrite core loss. First, a linear mathematical model of the ferrite core loss is formulated to characterize the hysteresis loss and the eddy current loss. The magnetic properties (the real and the imaginary components of the complex permeability) and the electric properties (the dielectric constant and the conductivity) are required. Second, the experimental procedures of those four properties are first presented. Toroids with 1.1 OD/ID ratios are selected as samples to obtain the magnetic properties. It is illustrated that the hysteresis loss should be measured at the frequency of interest, instead of DC, due to its frequency-dependence. The electric property data of ferrites are collected by using a disk sample which forms a capacitor. The conductivity tested is frequency-dependent due to the combination of the dielectric loss and the DC conduction loss. Finally, core loss simulations for the sample toroid, an EE core, and an RMIO core are performed and compared with the measurements. The flux and loss distributions are demonstrated in the last two cores. The hot spots are identified from the field plots. / Master of Science

In this study, a traffic generator software package namely MTGawn was developed to run packet generation and evaluation on a mobile device. The call generating software system is able to: simulate voice over Internet protocol calls as well as user datagram protocol and transmission control protocol between mobile phones over a wireless network and analyse network data similar to computer-based network monitoring tools such as Iperf and D-ITG but is self-contained on a mobile device. This entailed porting a ‘stripped down’ version of a packet generation and monitoring system with functionality as found in open source tools for a mobile platform. This mobile system is able to generate and monitor traffic over any network interface on a mobile device, and calculate the standard quality of service metrics. The tool was compared to a computer–based tool namely distributed Internet traffic generator (D-ITG) in the same environment and, in most cases, MTGawn reported comparable results to D-ITG. The important motivation for this software was to ease feasibility testing and monitoring in the field by using an affordable and rechargeable technology such as a mobile device. The system was tested in a testbed and can be used in rural areas where a mobile device is more suitable than a PC or laptop. The main challenge was to port and adapt an open source packet generator to an Android platform and to provide a suitable touchscreen interface for the tool. / >Magister Scientiae - MSc

Existing photomask metrology is struggling to keep pace with the rapid reduction of IC dimensions as traditional measurement techniques are being stretched to their limits. This thesis examines the use of on-mask probable electrical test structures and measurement techniques to meet this challenge and to accurately characterise the imaging capabilities of advanced binary and phase-shifting chrome-on-quartz photomasks. On-mask, electrical and optical linewidth measurement techniques have highlighted that the use of more than one measurement method, complementing each other, can prove valuable when characterising an advanced photomask process. Industry standard optical metrology test patterns have been adapted for the direct electrical equivalent measurement and the structures used to characterise different feature arrangements fabricated on standard and advanced photomasks with proximity correction techniques. The electrical measurements were compared to measurements from an optical mask metrology and verification tool and a state-of-the-art CD-AFM system and the results have demonstrated the capability and strengths of the on-mask electrical measurement. For example, electrical and AFM measurements on submicron features agreed within 10nm of each other while optical measurements were offset by up to 90nm. Hence, electrical techniques can prove valuable in providing feedback to the large number of metrology tools already supporting photomask manufacture, which in turn will help to develop CD standards for maskmaking. Electrical test structures have also been designed to enable the characterisation of optical proximity correction to characterise right angled corners in conducting tracks using a prototype design for both on-mask and wafer characterisation. Measurement results from the on-mask structures have shown that the electrical technique is sensitive enough to detect the effect of OPC on inner corners and to identify any defects in the fabricated features. For example less than 10 (5%) change in the expected resistance data trends indicated a deformed OPC feature. Results from on-wafer structures have shown that the correction technique has an impact on the final printed features and the measured resistance can be used to characterise the effects of different levels of correction. Overall the structures have shown their capability to characterise this type of optical proximity correction on both mask and wafer level. Test structures have also been designed for the characterisation of the dimensional mismatch between closely spaced photomask features. A number of photomasks were fabricated with these structures and the results from electrical measurements have been analysed to obtain information about the capability of the mask making process. The electrical test structures have demonstrated the capability of measuring tool and process induced dimensional mismatches in the nanometer range on masks which would otherwise prove difficult with standard optical metrology techniques. For example, electrical measurements detected mismatches of less than 15nm on 500nm wide features.

Photovoltaic (PV) conversion of solar energy appears to be one of the most promising ways of meeting the increasing energy demand. In space, photovoltaic power source is the only safe alternative. Conventional silicon solar cell technologies have seen several improvements and off late GaAs/Ge and multijunction solar cells are developed to improve conversion efficiency. Demand for higher power, smaller size, lesser weight and higher efficiency has necessitated the use of high frequency switching power conditioners, which requires a better understanding of the AC characteristics of the solar cell, especially its capacitance. Solar cell is large p-n junction diode, whose AC parameters (capacitance and resistance) varies nonlinearly with its operating voltage, temperature and depend on the method (frequency or time domain) of measurement.Hence, studies on AC parameters of solar cells is taken up involving development of instrumentation, measurements on various types of solar cells and applications of AC parameters on switching shunt regulators. In the present research work a measurement set-up to measure the solar cell AC parameters using impedance spectroscopy technique is established first with the commercial instruments. Here a small AC voltage (<VT) is applied about the operating voltage (DC bias) and its complex impedance is measured from the resultant current over a wide range of frequencies. Cell capacitance, parallel resistance, series resistance and inductance are estimated from the impedance spectrum, which is plot of the cell impedance in a complex plane. The principle of measurement, details of measurement set-up with calibration, testing and limitations observed when applied to solar cells, are presented. To over come the limitations in the measurement set-up, a dedicated userfriendly instrument called Solar Cell Impedance Analyser is developed to measure solar cell AC parameters. It is a personal computer based virtual instrument, which has a power amplifier, a high-speed data acquisition card and an arbitrary function generator card with a custom built micro controller based hardware with an application specific software developed using graphical programming language. A novel concept of software range extender is introduced, which virtually increases the dynamic range of the power amplifier.

Masters of Science / In this study, a traffic generator software package namely MTGawn was developed to run packet generation and evaluation on a mobile device. The call generating software system is able to: simulate voice over Internet protocol calls as well as user datagram protocol and transmission control protocol between mobile phones over a wireless network and analyse network data similar to computer-based network monitoring tools such as Iperf and D-ITG but is self-contained on a mobile device. This entailed porting a ‘stripped down’ version of a packet generation and monitoring system with functionality as found in open source tools for a mobile platform. This mobile system is able to generate and monitor traffic over any network interface on a mobile device, and calculate the standard quality of service metrics. The tool was compared to a computer–based tool namely distributed Internet traffic generator (D-ITG) in the same environment and, in most cases, MTGawn reported comparable results to D-ITG. The important motivation for this software was to ease feasibility testing and monitoring in the field by using an affordable and rechargeable technology such as a mobile device. The system was tested in a testbed and can be used in rural areas where a mobile device is more suitable than a PC or laptop. The main challenge was to port and adapt an open source packet generator to an Android platform and to provide a suitable touchscreen interface for the tool. ACM Categories and Subject Descriptors B.8 [PERFORMANCE AND RELIABILITY] B.8.2 [Performance Analysis and Design Aids] C.4 [PERFORMANCE OF SYSTEMS] Measurement techniques, Performance attributes

This dissertation describes the development of novel techniques for characterization of nonlinear properties of materials. The dissertation is divided into two parts, a background and theory section and a technique development section. In the background and theory section we explain the origins of the nonlinear optical response of materials across many different spatial and temporal scales. The mechanisms that we are most interested in are the electronic nuclear and reorientational responses, which occur on the range of sub-femtosecond to several picoseconds. The electronic mechanism is due to the electrons of a material experiencing a non-parabolic potential well due a strong electric field and occurs on the sub-femtosecond timescale. The nuclear or vibrational effect results from the motion of the nuclei of the atoms and typically occurs on the order of a few hundred femtoseconds. Finally the reorientational nonlinearity is due to the alignment of the molecule to the electric field, which alters the polarizability of the molecule and typically occurs on the scale of a few picoseconds. There are other mechanisms can induce nonlinear optical effects such as thermal effects and electrostriction, but these effects typically occur on much larger timescales than we are interested in, and hence will not be a major focus of this dissertation. In the nonlinear characterization techniques section, we describe previous research into the field of nonlinear optical characterization techniques, describing the techniques used to characterize the nonlinear properties of materials, their applications and limitations. We will trace the development of two recently developed techniques for nonlinear spectroscopy − the Dual Arm iii Z-Scan and the Beam Deflection techniques. The Dual Arm Z-Scan technique is an enhancement of the standard Z-Scan technique that allows for the measurement of small nonlinear signals in the presence of large background signals. This technique allows for the measurement of materials under certain conditions not previously measureable using the standard Z-Scan technique, such materials with low damage thresholds, poor solubility and thin films. In addition to the Dual Arm Z-Scan, we have developed a new method for characterizing nonlinear refraction, the Beam Deflection technique, which is a variation of the photothermal beam deflection technique previously used to measure very weak absorption signals. This technique offers relative ease of use, the ability to measure the absolute magnitude and sign of both the real and imaginary parts of � (3) simultaneously with high sensitivity. We fully develop the theory for materials with instantaneous and non-instantaneous nonlinearities, with nonlinear absorption and group velocity mismatch. We also demonstrate the power of this technique to separate the isotropic and reorientational contributions of liquids by examining the temporal response and polarization dependences. Lastly, we summarize our conclusions and describe two promising future research directions that would benefit from the Dual Arm Z-Scan and Beam Deflection techniques

A new pressure-measurement technique which employs the tools of molecular spectroscopy has recently received considerable attention in the fluid mechanics community. Measurements are made via oxygen-sensitive molecules attached to the surface of interest as a coating, or paint. The pressure-sensitive-paint (PSP) technique is now commonly used in stationary wind-tunnel tests; this thesis presents the extension of the technique to advanced turbomachinery applications. New pressure- and temperature-sensitive paints (TSPs) have been developed for application to a state-of-the-art transonic compressor where pressures up to 2 atm and surface temperatures up to 140° C are expected for the first-stage rotor. PSP and TSP data has been acquired from the suction surface of the first-stage rotor of a transonic compressor operating at its peak-efficiency condition. The shock structure is clearly visible in the pressure image, and visual comparison to the corresponding computational fluid dynamics (CFD) prediction shows qualitative agreement to the PSP data. / Master of Science

Buildings located near airports may be subjected to significant noise levels due to aircraft flyovers. Aircraft noise is particularly annoying when compared to other traffic noises due to its intermittent nature. While noise control is typically performed at the source, sound insulation programs are in place to improve the acoustic performance of a residence affected by the flyovers. Noise Level Reduction (NLR) is a common metric used in the United States to determine whether a residence qualifies for such programs. Sound insulation programs are available to houses that have an indoor Day Night Average Sound Level (DNL) greater than 45 dBA. NLR is a single-number metric used to quantify the ability for a building or building element to reduce the transmission of external sound pressure levels generated by aircraft. In addition to determining whether a residence qualifies, NLR can be used to quantify the effectiveness of the modifications performed as a result of the sound insulation program. NLR measurements with a loudspeaker offer an alternative method to those performed with aircraft flyovers, offering flexibility to the consultants that perform these measurements in the field. The purpose of this research was to better understand and improve the loudspeaker test for measuring NLR, providing a resource to the aircraft noise industry. Testing was completed on a "test house" that was constructed on campus with construction methods typical of a mixed-humid climate. The angular dependency, repeatability, and reproducibility of NLR, among other factors, were evaluated with field measurements. Significant NLR variations were observed with changes in lateral and vertical angles of incidence.